{ lib, pkgs, config, ... }:

let
  moduleName = "flatpaks";
  username = config.defaultUser or "henrov";
  flatpakConfPath = ./assets/system/apps/flatpaks.conf;

  enableProgram = config.enableFlatpaks or false;
in
{
  # Top-level toggle for this program
  options.enableFlatpaks = lib.mkEnableOption "Enable automatic Flatpak installation";

  # Define myApps top-level option if it doesn't exist yet
  options.myApps = lib.mkOption {
    type = lib.types.attrsOf lib.types.any;
    default = {};
    description = "Top-level container for custom apps";
  };

  config = lib.mkIf enableProgram {

    # myApps container
    myApps = {
      flatpaks = {
        enable    = true;
        user      = username;
        assetsDir = flatpakConfPath;
        files     = []; # we handle parsing at runtime
      };
    };

    # Deploy conf file
    environment.etc."flatpak/flatpaks.conf".source = flatpakConfPath;

    # Enable flatpak service
    services.flatpak.enable = true;
    xdg.portal.enable = true;

    # Systemd service for installing listed flatpaks
    systemd.services.flatpak-sync = {
      description = "Install Flatpak apps listed in flatpaks.conf";
      wantedBy    = [ "multi-user.target" ];
      wants       = [ "network-online.target" ];
      after       = [ "network-online.target" ];

      serviceConfig = {
        Type = "oneshot";
        ExecStart = ''
          set -euo pipefail
          CONF="${flatpakConfPath}"

          # Add flathub if missing
          if ! flatpak remotes --system --columns=name | grep -qx flathub; then
            flatpak remote-add --system --if-not-exists flathub https://dl.flathub.org/repo/flathub.flatpakrepo
          fi

          # Install apps listed in conf
          while read -r app; do
            app=$(echo "$app" | sed 's/#.*//;s/^[[:space:]]*//;s/[[:space:]]*$//')
            if [[ -n "$app" ]]; then
              if ! flatpak info --system "$app" >/dev/null 2>&1; then
                flatpak install --system -y --noninteractive flathub "$app"
              fi
            fi
          done < "$CONF"
        '';
      };

      restartTriggers = [ flatpakConfPath ];

      path = [
        pkgs.flatpak
        pkgs.coreutils
        pkgs.gnugrep
        pkgs.gnused
      ];
    };
  };
}